diff options
Diffstat (limited to 'arch/arm64/kernel/signal32.c')
| -rw-r--r-- | arch/arm64/kernel/signal32.c | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c new file mode 100644 index 000000000..24b09003f --- /dev/null +++ b/arch/arm64/kernel/signal32.c @@ -0,0 +1,516 @@ +/* + * Based on arch/arm/kernel/signal.c + * + * Copyright (C) 1995-2009 Russell King + * Copyright (C) 2012 ARM Ltd. + * Modified by Will Deacon <will.deacon@arm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ + +#include <linux/compat.h> +#include <linux/signal.h> +#include <linux/syscalls.h> +#include <linux/ratelimit.h> + +#include <asm/esr.h> +#include <asm/fpsimd.h> +#include <asm/signal32.h> +#include <asm/traps.h> +#include <linux/uaccess.h> +#include <asm/unistd.h> + +struct compat_sigcontext { + /* We always set these two fields to 0 */ + compat_ulong_t trap_no; + compat_ulong_t error_code; + + compat_ulong_t oldmask; + compat_ulong_t arm_r0; + compat_ulong_t arm_r1; + compat_ulong_t arm_r2; + compat_ulong_t arm_r3; + compat_ulong_t arm_r4; + compat_ulong_t arm_r5; + compat_ulong_t arm_r6; + compat_ulong_t arm_r7; + compat_ulong_t arm_r8; + compat_ulong_t arm_r9; + compat_ulong_t arm_r10; + compat_ulong_t arm_fp; + compat_ulong_t arm_ip; + compat_ulong_t arm_sp; + compat_ulong_t arm_lr; + compat_ulong_t arm_pc; + compat_ulong_t arm_cpsr; + compat_ulong_t fault_address; +}; + +struct compat_ucontext { + compat_ulong_t uc_flags; + compat_uptr_t uc_link; + compat_stack_t uc_stack; + struct compat_sigcontext uc_mcontext; + compat_sigset_t uc_sigmask; + int __unused[32 - (sizeof (compat_sigset_t) / sizeof (int))]; + compat_ulong_t uc_regspace[128] __attribute__((__aligned__(8))); +}; + +struct compat_vfp_sigframe { + compat_ulong_t magic; + compat_ulong_t size; + struct compat_user_vfp { + compat_u64 fpregs[32]; + compat_ulong_t fpscr; + } ufp; + struct compat_user_vfp_exc { + compat_ulong_t fpexc; + compat_ulong_t fpinst; + compat_ulong_t fpinst2; + } ufp_exc; +} __attribute__((__aligned__(8))); + +#define VFP_MAGIC 0x56465001 +#define VFP_STORAGE_SIZE sizeof(struct compat_vfp_sigframe) + +#define FSR_WRITE_SHIFT (11) + +struct compat_aux_sigframe { + struct compat_vfp_sigframe vfp; + + /* Something that isn't a valid magic number for any coprocessor. */ + unsigned long end_magic; +} __attribute__((__aligned__(8))); + +struct compat_sigframe { + struct compat_ucontext uc; + compat_ulong_t retcode[2]; +}; + +struct compat_rt_sigframe { + struct compat_siginfo info; + struct compat_sigframe sig; +}; + +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) + +static inline int put_sigset_t(compat_sigset_t __user *uset, sigset_t *set) +{ + compat_sigset_t cset; + + cset.sig[0] = set->sig[0] & 0xffffffffull; + cset.sig[1] = set->sig[0] >> 32; + + return copy_to_user(uset, &cset, sizeof(*uset)); +} + +static inline int get_sigset_t(sigset_t *set, + const compat_sigset_t __user *uset) +{ + compat_sigset_t s32; + + if (copy_from_user(&s32, uset, sizeof(*uset))) + return -EFAULT; + + set->sig[0] = s32.sig[0] | (((long)s32.sig[1]) << 32); + return 0; +} + +/* + * VFP save/restore code. + * + * We have to be careful with endianness, since the fpsimd context-switch + * code operates on 128-bit (Q) register values whereas the compat ABI + * uses an array of 64-bit (D) registers. Consequently, we need to swap + * the two halves of each Q register when running on a big-endian CPU. + */ +union __fpsimd_vreg { + __uint128_t raw; + struct { +#ifdef __AARCH64EB__ + u64 hi; + u64 lo; +#else + u64 lo; + u64 hi; +#endif + }; +}; + +static int compat_preserve_vfp_context(struct compat_vfp_sigframe __user *frame) +{ + struct user_fpsimd_state const *fpsimd = + ¤t->thread.uw.fpsimd_state; + compat_ulong_t magic = VFP_MAGIC; + compat_ulong_t size = VFP_STORAGE_SIZE; + compat_ulong_t fpscr, fpexc; + int i, err = 0; + + /* + * Save the hardware registers to the fpsimd_state structure. + * Note that this also saves V16-31, which aren't visible + * in AArch32. + */ + fpsimd_signal_preserve_current_state(); + + /* Place structure header on the stack */ + __put_user_error(magic, &frame->magic, err); + __put_user_error(size, &frame->size, err); + + /* + * Now copy the FP registers. Since the registers are packed, + * we can copy the prefix we want (V0-V15) as it is. + */ + for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { + union __fpsimd_vreg vreg = { + .raw = fpsimd->vregs[i >> 1], + }; + + __put_user_error(vreg.lo, &frame->ufp.fpregs[i], err); + __put_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); + } + + /* Create an AArch32 fpscr from the fpsr and the fpcr. */ + fpscr = (fpsimd->fpsr & VFP_FPSCR_STAT_MASK) | + (fpsimd->fpcr & VFP_FPSCR_CTRL_MASK); + __put_user_error(fpscr, &frame->ufp.fpscr, err); + + /* + * The exception register aren't available so we fake up a + * basic FPEXC and zero everything else. + */ + fpexc = (1 << 30); + __put_user_error(fpexc, &frame->ufp_exc.fpexc, err); + __put_user_error(0, &frame->ufp_exc.fpinst, err); + __put_user_error(0, &frame->ufp_exc.fpinst2, err); + + return err ? -EFAULT : 0; +} + +static int compat_restore_vfp_context(struct compat_vfp_sigframe __user *frame) +{ + struct user_fpsimd_state fpsimd; + compat_ulong_t magic = VFP_MAGIC; + compat_ulong_t size = VFP_STORAGE_SIZE; + compat_ulong_t fpscr; + int i, err = 0; + + __get_user_error(magic, &frame->magic, err); + __get_user_error(size, &frame->size, err); + + if (err) + return -EFAULT; + if (magic != VFP_MAGIC || size != VFP_STORAGE_SIZE) + return -EINVAL; + + /* Copy the FP registers into the start of the fpsimd_state. */ + for (i = 0; i < ARRAY_SIZE(frame->ufp.fpregs); i += 2) { + union __fpsimd_vreg vreg; + + __get_user_error(vreg.lo, &frame->ufp.fpregs[i], err); + __get_user_error(vreg.hi, &frame->ufp.fpregs[i + 1], err); + fpsimd.vregs[i >> 1] = vreg.raw; + } + + /* Extract the fpsr and the fpcr from the fpscr */ + __get_user_error(fpscr, &frame->ufp.fpscr, err); + fpsimd.fpsr = fpscr & VFP_FPSCR_STAT_MASK; + fpsimd.fpcr = fpscr & VFP_FPSCR_CTRL_MASK; + + /* + * We don't need to touch the exception register, so + * reload the hardware state. + */ + if (!err) + fpsimd_update_current_state(&fpsimd); + + return err ? -EFAULT : 0; +} + +static int compat_restore_sigframe(struct pt_regs *regs, + struct compat_sigframe __user *sf) +{ + int err; + sigset_t set; + struct compat_aux_sigframe __user *aux; + unsigned long psr; + + err = get_sigset_t(&set, &sf->uc.uc_sigmask); + if (err == 0) { + sigdelsetmask(&set, ~_BLOCKABLE); + set_current_blocked(&set); + } + + __get_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); + __get_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); + __get_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); + __get_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); + __get_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); + __get_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); + __get_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); + __get_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); + __get_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); + __get_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); + __get_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); + __get_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); + __get_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); + __get_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); + __get_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); + __get_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); + __get_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err); + + regs->pstate = compat_psr_to_pstate(psr); + + /* + * Avoid compat_sys_sigreturn() restarting. + */ + forget_syscall(regs); + + err |= !valid_user_regs(®s->user_regs, current); + + aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; + if (err == 0) + err |= compat_restore_vfp_context(&aux->vfp); + + return err; +} + +COMPAT_SYSCALL_DEFINE0(sigreturn) +{ + struct pt_regs *regs = current_pt_regs(); + struct compat_sigframe __user *frame; + + /* Always make any pending restarted system calls return -EINTR */ + current->restart_block.fn = do_no_restart_syscall; + + /* + * Since we stacked the signal on a 64-bit boundary, + * then 'sp' should be word aligned here. If it's + * not, then the user is trying to mess with us. + */ + if (regs->compat_sp & 7) + goto badframe; + + frame = (struct compat_sigframe __user *)regs->compat_sp; + + if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) + goto badframe; + + if (compat_restore_sigframe(regs, frame)) + goto badframe; + + return regs->regs[0]; + +badframe: + arm64_notify_segfault(regs->compat_sp); + return 0; +} + +COMPAT_SYSCALL_DEFINE0(rt_sigreturn) +{ + struct pt_regs *regs = current_pt_regs(); + struct compat_rt_sigframe __user *frame; + + /* Always make any pending restarted system calls return -EINTR */ + current->restart_block.fn = do_no_restart_syscall; + + /* + * Since we stacked the signal on a 64-bit boundary, + * then 'sp' should be word aligned here. If it's + * not, then the user is trying to mess with us. + */ + if (regs->compat_sp & 7) + goto badframe; + + frame = (struct compat_rt_sigframe __user *)regs->compat_sp; + + if (!access_ok(VERIFY_READ, frame, sizeof (*frame))) + goto badframe; + + if (compat_restore_sigframe(regs, &frame->sig)) + goto badframe; + + if (compat_restore_altstack(&frame->sig.uc.uc_stack)) + goto badframe; + + return regs->regs[0]; + +badframe: + arm64_notify_segfault(regs->compat_sp); + return 0; +} + +static void __user *compat_get_sigframe(struct ksignal *ksig, + struct pt_regs *regs, + int framesize) +{ + compat_ulong_t sp = sigsp(regs->compat_sp, ksig); + void __user *frame; + + /* + * ATPCS B01 mandates 8-byte alignment + */ + frame = compat_ptr((compat_uptr_t)((sp - framesize) & ~7)); + + /* + * Check that we can actually write to the signal frame. + */ + if (!access_ok(VERIFY_WRITE, frame, framesize)) + frame = NULL; + + return frame; +} + +static void compat_setup_return(struct pt_regs *regs, struct k_sigaction *ka, + compat_ulong_t __user *rc, void __user *frame, + int usig) +{ + compat_ulong_t handler = ptr_to_compat(ka->sa.sa_handler); + compat_ulong_t retcode; + compat_ulong_t spsr = regs->pstate & ~(PSR_f | PSR_AA32_E_BIT); + int thumb; + + /* Check if the handler is written for ARM or Thumb */ + thumb = handler & 1; + + if (thumb) + spsr |= PSR_AA32_T_BIT; + else + spsr &= ~PSR_AA32_T_BIT; + + /* The IT state must be cleared for both ARM and Thumb-2 */ + spsr &= ~PSR_AA32_IT_MASK; + + /* Restore the original endianness */ + spsr |= PSR_AA32_ENDSTATE; + + if (ka->sa.sa_flags & SA_RESTORER) { + retcode = ptr_to_compat(ka->sa.sa_restorer); + } else { + /* Set up sigreturn pointer */ + unsigned int idx = thumb << 1; + + if (ka->sa.sa_flags & SA_SIGINFO) + idx += 3; + + retcode = AARCH32_VECTORS_BASE + + AARCH32_KERN_SIGRET_CODE_OFFSET + + (idx << 2) + thumb; + } + + regs->regs[0] = usig; + regs->compat_sp = ptr_to_compat(frame); + regs->compat_lr = retcode; + regs->pc = handler; + regs->pstate = spsr; +} + +static int compat_setup_sigframe(struct compat_sigframe __user *sf, + struct pt_regs *regs, sigset_t *set) +{ + struct compat_aux_sigframe __user *aux; + unsigned long psr = pstate_to_compat_psr(regs->pstate); + int err = 0; + + __put_user_error(regs->regs[0], &sf->uc.uc_mcontext.arm_r0, err); + __put_user_error(regs->regs[1], &sf->uc.uc_mcontext.arm_r1, err); + __put_user_error(regs->regs[2], &sf->uc.uc_mcontext.arm_r2, err); + __put_user_error(regs->regs[3], &sf->uc.uc_mcontext.arm_r3, err); + __put_user_error(regs->regs[4], &sf->uc.uc_mcontext.arm_r4, err); + __put_user_error(regs->regs[5], &sf->uc.uc_mcontext.arm_r5, err); + __put_user_error(regs->regs[6], &sf->uc.uc_mcontext.arm_r6, err); + __put_user_error(regs->regs[7], &sf->uc.uc_mcontext.arm_r7, err); + __put_user_error(regs->regs[8], &sf->uc.uc_mcontext.arm_r8, err); + __put_user_error(regs->regs[9], &sf->uc.uc_mcontext.arm_r9, err); + __put_user_error(regs->regs[10], &sf->uc.uc_mcontext.arm_r10, err); + __put_user_error(regs->regs[11], &sf->uc.uc_mcontext.arm_fp, err); + __put_user_error(regs->regs[12], &sf->uc.uc_mcontext.arm_ip, err); + __put_user_error(regs->compat_sp, &sf->uc.uc_mcontext.arm_sp, err); + __put_user_error(regs->compat_lr, &sf->uc.uc_mcontext.arm_lr, err); + __put_user_error(regs->pc, &sf->uc.uc_mcontext.arm_pc, err); + __put_user_error(psr, &sf->uc.uc_mcontext.arm_cpsr, err); + + __put_user_error((compat_ulong_t)0, &sf->uc.uc_mcontext.trap_no, err); + /* set the compat FSR WnR */ + __put_user_error(!!(current->thread.fault_code & ESR_ELx_WNR) << + FSR_WRITE_SHIFT, &sf->uc.uc_mcontext.error_code, err); + __put_user_error(current->thread.fault_address, &sf->uc.uc_mcontext.fault_address, err); + __put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err); + + err |= put_sigset_t(&sf->uc.uc_sigmask, set); + + aux = (struct compat_aux_sigframe __user *) sf->uc.uc_regspace; + + if (err == 0) + err |= compat_preserve_vfp_context(&aux->vfp); + __put_user_error(0, &aux->end_magic, err); + + return err; +} + +/* + * 32-bit signal handling routines called from signal.c + */ +int compat_setup_rt_frame(int usig, struct ksignal *ksig, + sigset_t *set, struct pt_regs *regs) +{ + struct compat_rt_sigframe __user *frame; + int err = 0; + + frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); + + if (!frame) + return 1; + + err |= copy_siginfo_to_user32(&frame->info, &ksig->info); + + __put_user_error(0, &frame->sig.uc.uc_flags, err); + __put_user_error(0, &frame->sig.uc.uc_link, err); + + err |= __compat_save_altstack(&frame->sig.uc.uc_stack, regs->compat_sp); + + err |= compat_setup_sigframe(&frame->sig, regs, set); + + if (err == 0) { + compat_setup_return(regs, &ksig->ka, frame->sig.retcode, frame, usig); + regs->regs[1] = (compat_ulong_t)(unsigned long)&frame->info; + regs->regs[2] = (compat_ulong_t)(unsigned long)&frame->sig.uc; + } + + return err; +} + +int compat_setup_frame(int usig, struct ksignal *ksig, sigset_t *set, + struct pt_regs *regs) +{ + struct compat_sigframe __user *frame; + int err = 0; + + frame = compat_get_sigframe(ksig, regs, sizeof(*frame)); + + if (!frame) + return 1; + + __put_user_error(0x5ac3c35a, &frame->uc.uc_flags, err); + + err |= compat_setup_sigframe(frame, regs, set); + if (err == 0) + compat_setup_return(regs, &ksig->ka, frame->retcode, frame, usig); + + return err; +} + +void compat_setup_restart_syscall(struct pt_regs *regs) +{ + regs->regs[7] = __NR_compat_restart_syscall; +} |